Plastic floating drill pipe and sucker rod protector



Sept. 15, 1970 c. H. COLLETT PLASTIC FLOATING DRILL PIPE AND SUCKER RODPROTECTOR Filed March 25, 1969 Fig./

' INVENTOR vCharles H. Col/eff lUnited States Patent O 3,528,499 PLASTICFLOATING DRILL PIPE AND SUCKER ROD PROTECTOR Charles H. Collett, P.O.BOX 411, Menlo Park, Calif. 94025 Filed Mar. 25, 1969, Ser. No. 810,136Int. Cl. E21b 37/02 U.S. Cl. 166-175 6 Claims ABSTRACT OF THE DISCLOSUREA protector for an oil well bore tube and casing for use in combinationwith an oil well drill pipe or sucker rod utilizes a novel constructionwhich makes possible taking advantage of the unusual benets of allplastic material in its construction. This combination further makespossible successful utilization of a floating relationship between the'bore tube and the drill pipe or sucker rod. The construction permitsrapid installation and replacement of the protector, increases itseifectiveness with use, avoids jamming in the tube and on the pipe orrod. and permits elimination of metallic components in the protector andtheir attendant hazard to the well in case of failure of the protector.

BACKGROUND OF THE INVENTION The drilling or pumping of oil wells has formany years presented a diiiicult problem of maintaining the properrelationship between the drill pipe or the sucker rod and the well boretube or casing. The basic problem arises from the great depths,temperatures, and pressures involved in these operations, the diflicultyof avoiding bends and crookedness in the bore hole and consequently inmaintaining proper alignment between the drill tube or sucker rod andthe bore tube or casing to insure proper operation of these devices.

Some of the more specific problems well known to those skilled in theart and which have vbeen `worked on many times, and the attempts made tosolve them may be brieily summed up as follows:

(A) Drill tube or sucker rod must have flexibility to permit smoothoperation in the tube or casing, which latter is often in a bad state ofalignment or crookedness.

(B) The protectors used must not bind against the sides of the tubeduring operation.

(C) The protectors must not jam up against the tapered end of the tubeor rod causing their expansion and binding in the tube.

(D) The protectors must permit free flow of drilling mud or oil throughor around them and hence through the casing.

(E) The protectors should permit of easy installation on the pipe orrod, as `well as ready removal and replacement.

` (F) The protectors should be preferably free of metallic componentswhich would jam the operation in the event of failure of the protectors.

One basic method of attempting to solve some of these problems wasconcerned with use of elastomeric materials for fabrication of theprotectors. This method alone had many shortcomings in that most rubber,or similar compounds, must be made oil, heat, and cold resisting inorder to be serviceable in this application. Ordinary rubber, of course,is not satisfactory. In addition the material must be flexible and havea low coeicient of friction. The configuration also must be such as toavoid jamming either in the casing or up against the tapers on the rodsand to overcome this and related problems metallic inserts have beenused in combination with elastomeric material. This, of course, createda problem of difficulty in Patented Sept. 15 1970 ICC installing andreplacing the protectors, as well as the hazard of introducing foreignmetal into the well as mentioned above.

In the case of drill pipes, the principle of a oating protector in whichthe latter has sufficient clearance to permit it to ride up and downalong the drill rod and thus avoid binding at any one particular pointhas been used. While this represented some improvement, there was stillthe problem of the protector rising up against the tapered section ofthe rod spreading out because of the relationship at that point and thuseliminating the clearance and resulting in jamming again. Protectors ofthis type, which are sometimes referred to as stabilizers in the art,when used in connection with drill pipes, have never been applied tosucker rods. The tremendous forces encountered during the upward motionof the sucker rod in particular causes such a oating protector to traveldownwards during the upstroke of the sucker rod and invariably swell outover the taper and jam in the tube. On drill pipes, of course, theeifect is the opposite due to circulation of drill mud.

Among the many attempts to overcome these problems some of theoutstanding ones are represented by my Pat. No. 3,019,063 and mycopending patent application No. 701,641 led Jan. 30, 1968. While thesehave been quite successful, the problems enumerated above still exist toa considerable degree and have not been solved until my presentinvention which is described more fully below.

SUMMARY OF THE INVENTION I have discovered that by the use of the allplastic one piece construction of my invention, together with my joiningmethod, I am able to iinally solve the problems enumerated above. Morespecically, I have discovered that the use of such an all plasticconstruction of the type and conguration which I disclose below, incombination with metallic drill pipes and sucker rods, produces anunusual result insofar as the relationship Ibetween the plasticconstruction and the well elements themselves is concerned.

I have discovered further that the method of my invention which relatesto the joining of my protector when placed in operation in combinationwith oil well elements as well as the eiects of the oil itself and/orthe drilling mud used, produces still further unusual results inconnection with the solution of the problems.

I have discovered further that the combination of materials andconstruction which I disclose herein makes it possible to utilize afloating protector and realize the` benefits thereof, not only in adrill pipe protector but in a sucker rod protector as well.

DESCRIPTION OF THE DRAWINGS FIG. l is a longitudinal section through awell casing or bore showing a typical drill pipe or sucker rod inposition with the protector of my invention.

FIG. 2 is allongitudinal elevation of the protector of my invention inthe direction 2 2 of FIG. l.

FIG. 3 is a top View of the protector of my invention.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawing,there is seen the Shaft 1 of the drill pipe or sucker rod, as the casemay be. A central channel 2 comprises a hollow concentric section in rod1 for the purpose of circulating drill mud in the case of drill rodapplications. Tapered sections 3 which join with the shaft section 1provide the necessary increase in diameter for coupling members 4. Thelatter are threaded members used for interconnecting successive sectionsof drill pipe or sucker rod, as is well known to those skilled in theart.

The bore tube or well casing is likewise an element of the well, wellknown to the art.

The protector body itself 6, is provided with a connecting pin 7 whichserves to lock in position the interlocking joint 8. The latter is ofirregular or staggered construction to provide overlapping orinterlocking between opposite faces of the split in the body 6 of whichit comprises the connecting or adjoining edges.

Outer grooves 9, which comprise a series of longitudinal grooves in theouter surface of body member 6, and inner grooves 10 which providecorresponding grooves on the inner surface of body member 6, provide forcirculation of drilling mud in the case of drill pipes, and for the flowof oil in the case of `sucker rods.

It should now be apparent to those skilled in the art that body member 6is capable of easy opening or flexing about its central axis and thus isplaced in position around the shaft 1 of a drill pipe orsucker rod.Because of its resilp iency body member 6, after being placed aroundshaft member 1, may be brought together so that its lengthwise split orjoint 8 may come together and interlock as shown. Connecting pin 7 maythen be inserted through suitably aligned holes in joint 8, thus xingprotectors 6 in relation to shaft 1.

Body member 6 and pin 7 are made of plastic materials. These may beanyone of a number of suitable plastics, but I have discovered thatthose of the Plaskon type which are compounded from urea, formaldehyderesin are especially suitable. One particular type known as Plaskon 8200HS manufactured by Allied Chemical Company, well known to the plasticart, is especially suitable for this purpose.

In addition to the ease of installation, replacement and removal of myprotector, which should now 'be evident from the disclosure-above, I amable with this construction and combination to maintain properclearances between my shaft 1 and the central opening of my body member6 as Well as 'between the outside diameter of my body member 6 and theinside diameter of bore tube or well casing 5. This permits me to employthe oating relationship between drill pipe or sucker rod and the wellcasing discussed above. I have found, for example, that a clearance ofapproximately 1/16 of an inch between shaft 1 and the central opening ofmember 6 when used in combination With the materials disclosed herein,provides adequate clearance for the floating of member 6 upon shaft 1. Ihave found further that a clearance of approximately 1A of an inch to1/2 of an inch between the outside diameter of member 6 and the insidediameter of bore tube 5 is adequate to take care of most conditionsencountered in bore tubes.

What is of significant importance is, I have discovered that when usingVa plastic material of the class described herein in combination withthe Imetallic elements of the drill shaft 1 and well casing 5, plus theeffect of the drill mud or oil, a strengthening or stabilizing effect isproduced on the plastic materials which tend to strengthen them againstdeformation. This applies equally to the connecting pin 7 so that theentire assembly of my protector acquires greater strength againstdeformation while retaining its inherent flexible properties soimportant in this operation as disclosed above.

The foregoing has two very important and unusual effects in the solutionof the problems which this invention solves. The strengthening effect ofthe combination of plastic, metal, and oil upon the properties of theplastics I employ permits my protector 6 to travel up in the case ofsucker rods or down in the case of drill pipes with proper frictionalrelationship on all surfaces and yet prevents it from expanding unduly,or even noticeably when it strikes the tapered sections 3. The othereffect of this result which my combination produces is that the strengthof my protector thus attained precludes the necessity of use of anymetallic inserts or supplementary elements to achieve the mechanicalstrength required. The ease of installation and removal which has beendisclosed above is still present and evident to those skilled in theart.

I claim:

1. A plastic protector for drill pipes or sucker rods in oil wellscomprising:

a hollow cylindrical body member having a single lengthwise splittherein; v

said lengthwise split characterized by a broken line defininginterlocking sections in said body member on opposing sides of saidsplit;

a longitudinal hole running lengthwise through said 'body and'throughsaid interlocking sections;

a plastic pin member disposed for insertion in said hole and throughsaid interlocking sections;

a plurality of longitudinal grooves around the outer circumference ofsaid body member and extending through the length thereof;

a plurality of longitudinal grooves around the inner circumference ofsaid body member and extending through the length thereof;

said protector being further characterized by the absence of anymetallic parts whatsoever.

2. The protector of claim 1 in which said body member and said pinmember are composed of a plastic material compounded fromurea-formaldehyde resin.

3. The protector of claim 1 in which said body member and said pinmember are composed of one of a class of plastic materials known asPlaskon.

4. The protector of claim 1 in which said body member and said pinmember are composed of a plastic material known as Plaskon 8200 HS.

5. The protector of claim 1 in com-bination with an oil well drill tubeand casing in which the clearance between the inside diameter of saidprotector and the outside diameter of said tube is yapproximatelyone-sixteenth of an inch and the clearance between the outside diameterof said protector and the inside diameter of said casing isapproximately one-half inch.

6. The protector of claim 1 in combination with an oil well sucker rodand casing in Iwhich the clearance between the inside diameter of saidprotector and the outside diameter of said tube is approximatelyone-sixteenth of an inch and the clearance between the outside diameterof said protector and the inside diameter of said casing isapproximately one-half inch.

' References Cited UNITED STATES PATENTS 3,019,063 1/ 1962 Collett 308-43,058,524 10/ 1962 Tripplehorn 166 176 3,197,262 7/ 1965 Fairchild 308-43,227,498 1/1966 Leathers 308-4 3,330,359 7/1967 Ward 166-176 X3,414,337 1'2/1968 Sable 166-176 X 3,425,757 2/ 1969 Minor 308-4 DAVIDH. BROWN, Primary Examiner 'U.S. Cl. X.R.

